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The following mechanism is used by an R/3 work process to connect to the database as user

SAPSR3:

1) A connection to the database is made as user OPS$ (UNIX: OPS$adm , NT:

OPS$SAPService ) with very few privileges.

2) User OPS$ is the owner of table SAP USER. From this table, the password for user SAPSR3

is retrieved and the database session for user OPS$ is terminated.

3) The work process now connects as user SAPSR3 with the password from table SAP USER.

To allow R/3 work processes to connect over the network using the OPS$ mechanism, the

init.ora parameter REMOTE_OS_AUTHENT must be set to TR UE. This allows

remote OS authentication for OS users with an OPS$ user on any computer in the network in

Which the database is accessible.

To change the password of user SAPSR3 , perform the following:

For UNIX: Use program SAPDBA to perform the required actions

For NT: Connect to Oracle as user OPS$SAPService, and:

Change the password entry for user SAPSR3 in table SAP USER

Change the password of user SAPSR3

If an R/3 instance is running on a server other than the database server, R/3 work processes

And their dedicated shadow processes communicate over a network. As communication

Protocol, TCP/IP is used.

The work processes of an R/3 instance configured on the database Server use the IPC protocol to

communicate with dedicated shadow processes running on the Same server.

For Net8 to accept connections on the database server, the listener must be running. The

Oracle utility ls nrct l is used to start and stop the listener and to check the status of Net8

connections. In a UNIX environment, the process tn sls nr is started. On NT, the service

"Oracle TNSListener" is started.

Three operating system files are used in a NET8 configuration. You can find these files in the

ORACLE_HOME subdirectory network/admin (NT: net80\admin ) on each application server

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and on the database server :

tnsnames.ora : Contains a list of service names for all databases that can be accessed in the

network

sqlnet.ora : Contains client side default domain information and optional diagnostic

parameters used for client tracing and logging

listener.ora :Only used on a database server machine. Contains Oracle system IDs for

which the listener can receive connections, and various control parameters used by program

ls nrct l

DB24 :

Use the DBA operations monitor for online monitoring of database operations. You can also

Monitor the runtime and the remaining time of operations that are running. The DBA

Operations monitor provides historical as well as current (online ) information about the

Following database operations :

Backup/recovery (for example, backing up or recovering the database )

Performance (for example, checking, creating, updating and deleting database statistics )

The memory structure (for example, space information for database objects, reorganizing

Database objects, or extending and deleting database objects ).

Database checks (for example, checking the database for critical situations )

Configuration (for example, configuring database parameters )

You can call up the SAP DB A functions from an ASC II interface, or you can use a command

Option to configure and execute the functions individually. The administration tool SAPDBA

For Oracle and its backup tools BRBACK UP, BRARCH IVE and BRRES TORE support the

Database administrator both in daily routine tasks and in less frequent, more complex tasks,

Such as recovering or reorganizing the database.

To enable SAP DB A to function properly, you must configure init< SID> .dba file.

Make sure you have the latest patch installed for SAPDBA. To check SAPDBAs patch

Management concept, refer to SAP Notes 126769 and 141999.

S tages While S tarting Oracle:

1) In the N o mount phase, the database instance is built up. Operating system resources

are Allocated using configuration information stored in the profile init.ora.

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2) In the M ount phase, the control files of the database are evaluated. The system reads

the Information about the file structure of the database. Data files and logs are not yet opened.

3) In the Open phase, all files in the database system are opened. If required, an instance

Recovery is performed immediately after opening the database. Pending database

Transactions are ended.

SHUTDOW N NORMAL S TAR TUP NOMO UNT

SHUTDOW N IMMED IATE STAR TUP MO UNT

SHUTDOW N ABOR T STAR TUP OPE N

An Oracle database system has three processes that write information from the Shared Global

Area (SGA) to the appropriate files :

1)During a checkpoint, the database writer (DBWR ) asynchronously writes the changed

blocks from the SGA to the database data files

2)To speed up the writing of checkpoints, the checkpoint process (CKP T) is started

3)The logwriter (LGWR ) synchronously writes the change log from the SGA redo log buffer

to the currently active online redo log file

In a production database system, the database must always run in ARCHIVELOG mode and

have the archiver process (ARCH) started (init. ora: log_archive_start = TRUE ). ARCH

archives a completed online redo log file into an offline redo log file in the archive directory.

ARCH determines the archive directory from the init< SID> .ora parameter log_archive_dest (default : ?/ saparch/) and determines the file name from the parameter l og_archive_format .

Once the offline redo log file has been successfully created, the corresponding online redo log

file is released to be overwritten with new log information.

If no free space is available in the archive directory, the archiver does not archive the file.

After a corresponding number of redo log switches, the database becomes "stuck". Database

changes cannot be committed as long as this archiver stuck situation persists.

A database is divided into logical storage units called table spaces. Table spaces are divided

into logical units of storage called segments (tables/indexes ). Segments are further divided

into extents, which consist of contiguous data blocks. A data block (normally 8K ) is the

smallest unit of I/O used by a database.

A tablespace in an Oracle database consists of one or more physical data files. A data file can

be associated with only one tablespace.

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You can increase a tablespace in two ways:

1) Add a data file to a tablespace. When you add another data file to an existing tablespace,

you increase the amount of disk space allocated for the corresponding tablespace.

2) Increase the size of a data file.

Storage parameters such as INITI AL EXT E NT, NEXT EXTE NT and MA X EXTE NT allow

you to manage space allocated to a table.

For performance reasons, operating system block size should be the same as Oracle data

block size.

The Oracle database uses tablespaces. From a logical point of view, a tablespace is a

container for database objects, such as tables and indexes. On disk, a tablespace consists of

one or more data files. You can increase the capacity of a tablespace by adding files to it.

The R/3 naming convention for tablespace names is defined as follows :

PSAP.

The abbreviations in the tablespace name are part of the directory name and file name of each

data file. Directories and data files are numbered.

The objects located in the tablespaces SYSTEM , PSAPROLL , and PSAPTEMP belong either

to the Oracle database users SYS or SYS TEM. Do not create any objects owned by

other users in these tablespaces.

The objects located in the other tablespaces belong to the R/3 database user SAPSR3 . R/3

System users do not have a database system user.The R/3 System and SAP tools, such as SAP DB A , require that the naming conventions be

observed. The installed system constitutes a logical unit, which you should not change. In this

way, SAP can ensure that you receive fast and efficient support.

D irectory and file names are standardized in the R/3 environment. We recommend that you

use the following standards:

y Tablespace files reside in the sapdata directories

y The online redo log files reside in the origlog and mirrlog directories

y The offline redo log files are written to the saparch directory

y There should be at least 3 copies of the Oracle control file on different disks

y The profile init< SID> .ora configures the Oracle instance, and resides in directory db s

(NT: databa se)

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The profile init< SID> .sap configures the backup tools brbackup and brarchive , and resides

in directory db s (NT: databa se)

The profile init< SID> .dba configures the SAP DB A tool, and resides in directory db s

(NT: databa se)

The Oracle alert file is written to directory saptrace / background

Trace files of the Oracle shadow processes are written to the directory saptrace / usertrace

During reorganization, export datasets are written to directory sapreorg

The directories saparch , sapcheck , sapreorg , and sapbackup are used by the SAP database

tools.

The names of the online redo log files are in table V$LOGFILE

The current log sequence number is the number of the redo log group with

the status current in table V$LOG